The present invention relates to systems and methods for illumination control and distribution during a vehicle bank, such as when vehicle banks in order to take a curve or to turn, and more specifically to illumination control and distribution systems and methods that control and maintain a pattern of light generally horizontal during the vehicle bank.
For example, FIG. 1 shows a motorcycle 40 traveling generally straight in a lane on a road 42. As can be seen, motorcycle headlights have a primarily horizontally shaped light beam pattern 44 that is shaped according to requirements to illuminate the road 42 ahead without disruptively shining on oncoming traffic, and to provide sufficient illumination for the drivers line of sight area 46. Unfortunately, the light beam pattern 44 suits illumination requirements when the motorcycle is traveling generally straight forward, but not when the motorcycle is banking.
When a vehicle such as the motorcycle 40 makes a turn, the motorcycle typically goes through some degree of bank angle, i.e., the motorcycle banks as the motorcycle is making a turn or traveling through a curve. Referring to FIG. 2, unfortunately, the headlight used in most motorcycles is secured to the motorcycle frame in a fixed position, which causes the horizontally shaped light beam pattern 44 cast by the motorcycle headlight to correspondingly tilt and bank as the motorcycle is banked on a curved road 48. The banking of the headlight along with the motorcycle 40 causes the amount of light distributed by the motorcycle headlight to shift in an inward and downward direction, which is away from the actual direction of travel of the motorcycle, and away from the focus of the motorcycle driver's eyes and line of sight area 46. This is particularly concerning for motorcycle drivers during cornering at night. With the amount of light distributed by the headlight light beam focused more in an inwardly direction, the driver's illuminated field of view generally forward of the direction of travel is reduced.
Attempts have been made to address the shortcomings of standard headlights that work well when the motorcycle is traveling straight ahead, but not when the motorcycle is banking. Systems have been suggested that include a velocity sensor along with several gyroscopes to detect the roll rate and the yaw rate of the motorcycle. Based on extensive calculations using the motion data from the gyroscopes and the velocity sensor, a mechanical system rotates or adjusts the rotational orientation about the optical axis of the headlight in a direction opposite to the bank angle of the motorcycle. Other systems mechanically move a mirror to adjust the direction of illumination coming from a fixed light source. Each of these systems requires complex computations, which require complex electronics, and they also require sophisticated mechanical systems to provide movement of the illumination from the light source. The mechanical systems add complexity and cost to both the headlight and the overall vehicle cost.
Some steerable headlights have been developed that address problems related to mechanically rotating headlights for automobiles. For instance, it is known to provide a one or two dimensional array of LEDs where the LEDs generate separate adjacent light fields and where different horizontal subsets of the LEDs may be illuminated to generate light patterns at different locations in front of the automobile. Although this type of arrangement may provide adjustable horizontal illumination for an automobile, it inadequately addresses the effect when a vehicle, such as a motorcycle, is banking. Merely providing additional illumination to the left or to the right fails to illuminate the portion of the curved road ahead of a motorcycle driver. The horizontal row of LEDs and associated horizontally shaped light beam pattern is still rotated off of horizontal and would tilt and bank during the vehicle bank (see FIGS. 1 and 2).
What is needed are systems and methods that accurately calculate a bank angle, and based upon the bank angle, alter a distribution of illumination to more naturally illuminate more of the driver's field of view.